1. Field of the Disclosure
The present disclosure relates to a rotary connector mounted in a vehicle such as an automobile, and more particularly to a rotary connector used to establish an electrical connection between a steering wheel side and a car body side with flat cables.
2. Description of the Related Art
Rotary connectors used to establish an electrical connection between the steering wheel side of an automobile and its car body side are known in art.
Japanese Unexamined Patent Application Publication No. 10-92541 describes a rotary connector (conventional example). In this disclosure a rotary connector 900 described in which an inner case 901 and an outer case 902 are combined so as to be relatively rotatable, a flat cable 904, which is wound, is stored in a space formed between the inner case 901 and the outer case 902, and an external conductor 905 is connected to a conductor 904a at each of the two ends of the flat cable 904 with a connecting part 906, as illustrated in FIG. 8A.
As illustrated in FIG. 8B, at the positive connecting part of the connecting part 906 between the external conductor 905 and the conductor 904a of the flat cable 904, the external conductor 905 and conductor 904a are electrically interconnected through a positive temperature coefficient (PTC) device 910.
With a disclosed technology, since the external conductor 905 and conductor 904a of the flat cable 904 are electrically interconnected through the PTC device 910, even if a circuit connected to the external conductor 905 is shorted, it is possible to prevent the flat cable 904 from being heated, melted, and broken.
In the conventional example described above, however, a PTC device is placed in the vicinity of a flat cable and the flat cable and PTC are directly interconnected. If an overcurrent flows and the PTC device thereby generates heat, the heat is transferred to the flat cable. This has been problematic in that the base material and exterior of the flat cable may be subjected to deterioration, separation, and other damage, the flat cable may thereby be locally bent, and at the worst, the flat cable may be broken.